Abstract
This study investigated the use of pulsed electric fields/PEF (electric field strengths 1–2 kV/cm, specific energy 9–127 kJ/kg) to facilitate calcium uptake into black beans in preserving their hardness from thermal degradation during subsequent cooking (1 h, 70–90 °C). Increasing specific energy reduced CaCl2 concentration in PEF processing media to 100 ppm to improve the hardness of cooked black beans. Those pre-treated at lower energy required min. 300 ppm CaCl2. Cooked black beans with PEF-pretreatment shared similar hardness as without PEF but unexpectedly chewier (18–43% more energy to disintegrate the beans). In vivo mastication study showed particle size at 18 and 24 s of mastication was significantly different (p < 0.05) wherein “PEF without CaCl2” had the smallest particles compared to “No PEF with CaCl2” and “PEF with CaCl2”. The outer seed coats of PEF-pretreated beans were easily masticated to smaller and consistent particles. This implies that PEF improved particle breakdown during mastication.
•Hardness, chewiness, cohesiveness, springiness and resilience of beans were measured•Specific energy input of PEF treatment influenced the chewiness of black beans•The texture of PEF-treated beans in calcium were chewier than untreated beans after cooking•PEF-treated black beans were masticated up to 30 s by 22 human subjects•Mastication of PEF-treated beans led to smaller and more consistent seed coat particles